The report was presented on Friday by Mario Poljak, a researcher at the Institute of Microbiology and Immunology, which led the study.

Poljak explained that the first estimate, presented on 6 May, had presumed a too high reliability of antibody tests and that the revised figures, based on new discoveries, are likely to be further fine-tuned in future follow-up reports, the final one being expected in November.

The researcher stressed that the antibody part of the study, executed with serological tests, had been far less relevant than the segment establishing only two positive Sars-CoV-2 cases in a representative sample of 1,368.

While explaining that the reliability estimate for the swab tests remained unchanged, Poljak argued this had been the figure that allowed the authorities to start easing restrictions.

Also important will be the follow-up findings based on reports being collected from all the participants of the study every three weeks to monitor their health condition and that of their remaining household members.